I'm having problems with all USB devices and have no idea how to fix them.

All deviced that are plugged in at system start time work perfectly but if I plug in a new device (eg a memory stick) it gets recognised by the computer (I get a audio tone to indicate connection) but I cannot see it in 'My Computer'.

I have software that syncs the contents on a removable hard drive. If the hard drive is plugged in at system start - everything is perfect, if I plug it in after the system has started the external hard drive cannot be seen but the sysn software still works.

I sometimes get the message of a USB1 device being plugged in even though I think that everything I have is USB2.

I've tried uninstalling all USB devices from the Device manager and re-installing but the problem remains